Components of certain equipment, such as that used in the petroleum and petrochemical industry, which includes the exploration, production, refining, manufacture, supply, transport, formulation or blending of petroleum, petrochemicals, or the direct compounds thereof, are often monitored to maintain reliable operation. However, such components can involve harsh conditions, such as high temperature, high pressure, and/or a corrosive environment, making it difficult or costly to obtain reliable measurements.
Determining flow distribution in refinery components or the like can facilitate the identification of hot spots, maldistribution, and other undesirable conditions. For example, monitoring hot spots and liquid maldistribution through a particulate bed, such as a reactor catalyst bed, an adsorbent bed, or a structured bed, can allow operators to take timely actions to avoid problematic conditions. For example, detecting a localized hot spot in a particulate bed in a fixed bed hydrotreating reactor, fixed bed hydrocracking reactor, or a vacuum tower wash section, can allow operators to avoid undesirable conditions in exothermic reactions. Additionally, monitoring liquid/gas flow distribution in a fixed reactor bed can be contribute to ensuring optical operation of the reactor, and can allow operators to alter the flow to increase utilization of the bed, increase the run-length, and thus enhance operations.
Conventional techniques for monitoring temperature distribution and flow of a fluid, such as for detection of hot spots and maldistribution, often rely on multiple thermocouples to monitor temperature distribution, e.g., inside fixed bed reactors. However, the number of thermocouples used for hot-spot detection within a particulate can be limited by the space inside the bed and the cost of installation and maintenance. Thus it can be difficult to provide adequate coverage inside the fixed bed space for hot spot detection. In addition, the temperature distribution measurement is an indirect indicator of the flow distribution. Therefore, flow conditions inferred from the limited point temperature measurements provided by thermocouples, constrained by the physical size of the thermocouples as well as the cost of installation and maintenance, can be inaccurate and unreliable.
Certain distributed optical fiber sensing technologies also have been proposed. However, the application of optical fiber sensors can be limited by harsh conditions, such as high temperature, high pressure and chemicals, such as hydrogen. For example, even special optical fibers and their protective coatings, such as those developed for down-hole applications, can be insufficient for long-term and reliable sensor deployment in more challenging environments, for example, in a hydrotreating or hydrocracking reactor. Furthermore, passive temperature measurements using distributed optical fiber sensors often involve low signal to noise ratio and provide only limited information about the properties of the surrounding media (i.e., the temperature at each sensor location at a given time). While additional properties of the surrounding media can in some circumstances, with suitable assumptions and boundary conditions, be inferred, such inferences are often inaccurate.
Accordingly, there is a continued need for improved techniques for determining the flow distribution of a fluid/gas through a component.